The optical art has provided many varieties of spectacles of the every-day type (for reading or distant viewing), industrial safety eyewear, soft plastic safety goggles (for use with power tools), ski and motorcycle goggles, swimming and underwater diving goggles. The every-day type of spectacle is designed to provide the wearer with corrective lenses for his eyes and usually the spectacle is not worn to obtain the protection provided by the other types of eyewear mentioned. The corrective spectacles and the types of goggles mentioned have developed largely independently, and at the present time a person desiring a corrective spectacle, a corrective safety goggle and corrective swimming and diving goggles has little choice but to purchase each type separately. Safety goggles, ski and motorcycle goggles may be purchased to fit over a small-size spectacle frame, but this is a bulky arrangement and it is uncomfortable to wear two eyepieces at the same time. It is not practical or even possible to wear every-day spectacles under swimming and diving goggles as the temples of the spectacles would break the watertight seal between the goggles and the face.
The aforesaid difficulties are substantially obviated by the present invention, which provides a spectacle frame which is apparently of the every-day type but which readily receives accessories which convert it into a safety goggle of the types mentioned, and also receives accessories which convert it to swimming and underwater diving goggles. The frame may carry optically neutral (plano) lenses which can be fitted when the frame is manufactured and which are used when the vision of the wearer does not require correction, or the frame can be supplied without lenses permitting prescription ground lenses to be fitted by others when the frame is sold to the ultimate user. The frame may be attached to the head by temples or by a headband, as may be most comfortable or required in any instance. When supplied with plano lenses the frame can receive 6-base ground and polished lenses which are optically superior to the flexible plastic "windows" provided by most goggles. The invention thus provides a person with normal vision with a spectacle which, after attachment of appropriate accessories, can be used for many mutually exclusive purposes without any distortion to his good vision and which provides a person with defective vision with an every-day spectacle having prescription ground lenses which can be converted to protective eyewear for shop safety, sport (motorcycling, skiing etc.) which meets health requirements (dry eye etc.), to a swimming goggle or to an underwater mask as may be desired.
More in detail, the invention provides a spectacle frame which has in its inner face a substantially circumferential channel adapted to retain with a tight fit a correspondingly ridged frame-to-face sealing component (hereinafter termed "seal"). The channel can be undercut to provide a tighter grip on the ridge, and at one or more places on its inner (rear) face the frame may have one or more holes or indentations to receive correspondingly positioned plugs in the ridge surface of the seal to facilitate positioning of the ridge of the seal with the channel of the frame, and to improve retention of the seal by the frame. Each side of the frame may carry a means for the attachment of a temple or a headband, each interchangable with the the other. The frame itself may have a wrap-around configuration to facilitate the receiving of the seals and to provide a wider arc of vision.
The invention further provides, as one of the aforementioned accessories, a frame-to-face seal for converting the frame into a goggle. The forward side of the seal is substantially flat and carries a circumferential retaining ridge which is adapted to mate with a corresponding circumferential channel in the rear side of the frame so as to engage the channel with a friction fit. The rear side of the seal is contoured to fit the face of the wearer closely. To convert the frame to a safety goggle the seal is inserted into the frame providing the wearer with eye protection around the outer sides, top and bottom of his eyes. An air space is provided between the eye cups to permit a stream of air to flow along the sides of the nose and through the nose bridge of the wearer in an amount which is necessary to prevent fogging of the lenses but which is not sufficient to cause drying of the eyes. The seals which convert the spectacle frame to a swimming goggle and to an underwater diving mask are of the single circumferential type that forms a watertight seal with the wearer's face, leaving the nose free to breathe in the swimming goggle, and completely sealing the nose in the diving mask. The watertight seal in the swimming goggle is attained with a face-formed flexible rubber or rubber-like skirt, or by the use of a continuous band of compressible foam rubber. The diving mask is constructed of a formed sheet of rubber or rubber-like material that provides a watertight fit around the eyes and nose of the wearer.
When used as an every-day spectacle and when used as a safety goggle, the frame is normally provided with temples which are preferably detachable. When the mask is used for swimming and diving, a headband must be attached either to the temple ends or to the frame replacing the temples, so that a watertight seal can be maintained.